JPS6188429A - Horizontal deflection circuit - Google Patents

Abstract

PURPOSE:To correct the linearity of a horizontal scanning beam in a television receiver by installing magnets near the right and the left ends of the opening of the deflection york in such a manner as to equalize the polarities of the magnets relative to the horizontal scanning beam. CONSTITUTION:Linear correction magnets 3 and 4 are installed near the right and the left ends of the opening of a deflection york 2 attached to a picture tube 1 in such a manner as to locate the S-poles on the scanning initiation side and locate the N-poles on the scanning termination side. An upward magnetic line of force is formed between the magnets 3 and 4 and the magnetic field strength at the start and the end of horizontal deflection is made greater than that at the geometrical center of the york 2. Accordingly, it is possible to easily correct horizontal linear strain which expands at the scanning initiation end and contracts at the scanning termination end without spending reactive power.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a horizontal deflection circuit in a television receiver or the like, and more particularly to linearity correction of a horizontal scanning beam.

[Background of the invention]

For such linearity correction, the linearity correction means is provided integrally with the deflection coil.1. Japanese Patent Publication No. 49-111
541 and JP-A-51-80122 are known. However, in these known examples, the conventional linearity correction coil is simply replaced with a new means, and there is no suggestion of a means for achieving complete linearity correction while also reducing the power consumption of the entire set.

[Purpose of the invention]

The purpose of the present invention is to perform complete linearity correction using the direct current magnetic field of a magnet with no power consumption.
Therefore, it is an object of the present invention to provide a horizontal deflection circuit equipped with horizontal linearity correction means that can reduce the power consumption of the deflection circuit and the entire set.

[Summary of the invention]

In order to achieve the above object, the present invention is characterized in that a pair of magnets with the same polarity in the vertical direction are arranged near the left and right ends of the deflection yoke opening. Furthermore, in the present invention, windings are provided on the pair of magnets, and an alternating current corresponding to the horizontal deflection current is passed through the windings. Another feature is that the linearity correction effect is improved.

[Embodiments of the invention]

A first example of arrangement of linearity correction magnets according to an embodiment of the present invention is shown below.
This is shown in Figures (α) and (h).

In FIG. 1(a), 1 is a cathode ray tube, 2 is a deflection yoke, and 5 is a linearity correction magnet.

This figure shows a cathode ray tube equipped with a deflection coil 2 and a linearity correction magnet 3, viewed from the side, and the electron beam is vertically deflected in the direction of the arrow.

FIG. 1(b) shows the deflection yoke 2 and the linearity correction magnet 5.
and 4 are viewed from the opening side of the deflection yoke 2. As shown in the figure, the magnets 5 and 4 are arranged so that they have 18 poles on the scanning start end side of the vertical deflection and N poles on the scanning end side of the vertical deflection.

Therefore, in the portion sandwiched between the magnets 5 and 4, lines of magnetic force are formed upward from below as shown by broken lines and arrows in the figure. The intensity distribution of the magnetic field formed by the magnets 5 and 4 is shown in Figure 1 (b
) is shown in Fig. 2 when viewed from the h-i cross section.

In Fig. 2, the 0 point on the horizontal axis indicating the position is the geometric center of the deflection yoke, that is, the position of the electron beam at the deflection yoke opening when the electron beam is not deflected, and the 8 point and the E point are respectively at the deflection yoke opening. The electron beam positions at the start and end of horizontal deflection are shown. That is, at the deflection yoke opening, the electron beam is horizontally deflected from 8 points to point E. Here, the magnetic field strength is strong at point 8 and point E, and weakest at point 0. Note that the distribution state of this magnetic field strength can be varied in various ways depending on the strength, shape, and relative placement position of magnets 5 and 4, but it is weakest near the 0 point, and stronger at points 8 and E than at the 0 point. The key point of the present invention is to arrange it so that it becomes the same.

In addition, in FIG. 1, the electron beam is also deflected in the vertical direction, but in order to avoid raster distortion, the magnets 51, 4
It is desirable that the effect on the electron beam is always constant for vertical deflection conditions.

That is, in the opening of the deflection yoke 2, it is desirable that the magnetic field generated by the magnets 5 and 4 within the range in which the electron beam is deflected has only a vertical component and almost no horizontal component.

For this purpose, the magnets 5 and 4 must be point symmetrical with respect to the deflection yoke center position 9 in FIG. 1(b), and the longitudinal center position of the magnet 5.4 must be on the extension of the horizontal scanning line. You can arrange it as you like.

Furthermore, in order to reduce the horizontal magnetic field component in the electron beam deflection region, the magnet 5.4 must have a certain length. The length of this magnet depends on the deflection angle of the cathode ray tube, etc., but generally it is sufficient that it has a length of approximately 115 mm or more of the diameter of the deflection yoke opening.

Now, horizontal linearity distortion in normal television receivers, etc. is caused by loss due to DC resistance in the deflection circuit, collector-emitter saturation voltage (VOE, aa) of the horizontal output transistor, etc.
E: For example, in a small television receiver where the power supply voltage of the horizontal deflection circuit is about 10 V, the influence of this Vogjaχ is large and cannot be ignored. ), etc., and it is well known that it has an exponential characteristic of elongating at the start end of the horizontal scan and contracting at the end of the horizontal scan.

Therefore, in order to correct this linearity distortion, it is necessary to make the correction so that it is shortened at the horizontal scanning start end and expanded at the horizontal scanning end end. In the conventional general horizontal linearity correction coil,
This correction was performed using changes in inductance connected in series with the horizontal deflection yoke, but the amount of correction required is large, especially in small television receivers where the power supply voltage of the horizontal deflection circuit is low and the initial distortion is large. Therefore, the inductance value connected in series with the upper horizontal deflection yoke cannot be ignored compared to the inductance value of the horizontal deflection yoke, and there is a problem that the reactive power in the horizontal deflection power is large.

However, in the embodiment of the invention shown in FIGS. 1 and 2, horizontal linearity distortion can be corrected without expending reactive power. That is, at the horizontal scanning start end side, the electron beam receives a force mainly due to the magnetic field from the magnet 3 in the opposite direction from the deflection magnetic field of the horizontal deflection yoke, and at the horizontal scanning end side, the electron beam receives a force from the deflection magnetic field of the horizontal deflection yoke. receives a force in the same direction as That is, it contracts on the horizontal scanning start end side and expands on the end side of the horizontal scan, thereby correcting the initial horizontal linearity distortion.

It is desirable that the magnetic field strength at point O in Figure 2 be 0, but if the linearity distortion is sufficiently corrected at points 8 and E, the magnetic field strength at point 0 will not become 0. There is. This indicates that the screen center position shifts according to the magnetic field strength, but this shift is caused by, for example, a two-pole magnet that has been commonly used in combination with a deflection yoke on the neck side of the cathode ray tube, i.e. This can be easily corrected using a centering magnet.

As explained above, according to the present invention, horizontal linearity distortion can be corrected by appropriately selecting the strength, shape, placement position, etc. of the magnet without introducing reactive power into the horizontal deflection circuit. be able to. It should be noted that in television receivers of the same type, the strength, shape, and arrangement position of the magnets are almost the same and the same degree of correction effect can always be obtained, and there is no need to make adjustments for each individual television receiver.

Next, a second embodiment of the present invention is shown in FIG. 5 and will be described in detail.

FIG. 3 shows the magnets 5 and 4 shown in FIG. 1(b) provided with windings 5 and 6, respectively, as shown. The terminals of the windings 5 and 6 are 7, 8, and 9.10, respectively, and alternating currents corresponding to the horizontal deflection currents are passed through the windings 5 and 6 through these terminals, respectively.

This current may be the horizontal deflection current itself flowing through the horizontal deflection yoke, or may be a sawtooth wave current obtained by integrating a horizontal synchronization signal or a horizontal flyback pulse. FIG. 5(a) shows a state in which the electron beam is at the horizontal scanning start end, and FIG. 5(b) shows a state in which the electron beam is at the horizontal scanning end.

In the state at the scanning start end side of FIG. , a magnetic field is generated as shown by dashed lines 11 and 12 and arrows.On the other hand, in the state at the end of scanning in FIG. Current is extracted from.

Therefore, this current generates a magnetic field shown by dashed lines 15 and 14 and arrows.

The magnetic fields indicated by broken lines 11 to 14 are alternating magnetic fields, and magnet 3
FIG. 4 shows the distribution state of the magnetic field strength combined with the DC magnetic field due to 4 and 4. Figure 4 shows the magnetic field distribution state by location using the same method as Figure 2, and the horizontal axis shows 8.0
．． The position including point E and the magnetic field strength are shown on the vertical axis. Moreover, FIG. 4(α) shows the state at the time when the electron beam is on the scanning start end side, that is, the state of FIG. 5(z), and FIG.
h) shows a state where the electron beam is at the end of scanning, that is, the state shown in FIG. 5(b). In addition, in Fig. 4, (A) is the DC magnetic field generated by the magnets 5, 4,
and an alternating magnetic field generated by an alternating current flowing through 6,
(c) shows a composite magnetic field obtained by combining the magnetic fields of (a) and (b).

The configuration shown in FIG. 5 is characterized in that the correction magnetic field at the required time and place can be used more effectively than in the cases shown in FIGS. 1 and 2. That is, at the time when the electron beam is on the scanning start end side, the corrected magnetic field strength is shown in Fig. 4 (α), but in this case, the composite magnetic field strength on the side of the 8 points where the electron beam exists in the deflection yoke opening is equal to that of the magnet. 5 and 4 compared to only the DC magnetic field,
Further, when the electron beam has a lateral pressure at the end of scanning as shown in FIG. 4Cb), the combined magnetic field strength on the side of point E where the electron beam exists is still larger than only the DC magnetic field generated by the magnets 5 and 4.

In the case of the embodiment shown in FIG. 3, the horizontal linearity distortion has been corrected in advance by the DC magnetic field generated by the magnets 5 and 4, so the amount of horizontal linearity distortion to be corrected by the current flowing through the windings 5 and 6 is different. It takes less. Therefore, windings 5 and 6
The number of turns can be reduced, and the reactive power when the windings 5 and 6 are connected in series to the deflection yoke can also be extremely small.

The method of connecting the windings 5 and 6 to the deflection yoke is as follows:
There are two ways as shown in Fig. 5(d) and (b).

In FIG. 5, 15 represents a horizontal deflection coil, and 16
, 17 are its two ends. , 5 to 10 are the same as those in FIG. That is, the windings 5 and 6 can be connected in series or in parallel, and in either case, the effect is almost the same, but the reactive power due to the element connected in series to the deflection yoke is reduced. The effect of
) is larger. The reasons for this are: firstly, the impedance decreases due to the parallel connection, and secondly: since the inductance of the required winding of windings 5 and 6 is smaller than the other winding inductance, most of the deflection current is This is because the current flows through the required winding. For example, the fifth
In Figure (α), that is, when the electron beam is at the scanning start end side, the polarity of the AC magnetic field 11 generated by the winding 5 is the same as the polarity of the DC magnetic field of the magnet 5, but the polarity of the AC magnetic field 11 generated by the winding 5 and the magnet 4 are
The magnetic field polarities of are opposite. Therefore, when the inductance of the winding 5 and the inductance of the winding 6 are compared, the inductance of the winding 5 is smaller, and more deflection current flows in the winding 5.

This is not shown in the graph of (b) in Figure 4 (α), but if this is taken into consideration, (b) of Figure 4 (α)
In the graph, the magnetic field strength at 8 points becomes thicker (the magnetic field strength at point E approaches 0).

Similarly, when the electron beam is at the end of scanning, as shown in Figure 5 (
In h), the inductance of the winding 5 becomes larger than the inductance of the winding 6, so that more deflection current flows through the winding 6, and the correction effect becomes larger.

Conversely, since the magnetic field strength required for correction is constant,
In the second embodiment, compared to the first embodiment, the DC magnetic field strength at the zero point can be made smaller, and therefore the amount of center shift of the image can be made smaller.

In the case of an electronic viewfinder that reflects the image with a mirror for viewing, the horizontal scanning may be reversed from left to right compared to a normal television receiver.
Just reverse the polarity.

〔Effect of the invention〕

As explained above, according to the first embodiment of the present invention, horizontal linearity correction can be performed without requiring any reactive power,
According to the second embodiment, compared to the conventional method, an extremely large correction effect can be obtained with extremely small reactive power.

Although the beam index method maintains uniformity of reproduced hue over the entire surface, it requires stricter horizontal linearity performance than the shadow mask method. In the conventional method using a linearity correction coil, which corrects linearity using the change in inductance value that occurs with the current value, it is extremely difficult to perform linearity correction ideally over the entire horizontal deflection range. was difficult. This is because it was necessary to simultaneously correct the horizontal scanning start side and end side, which require different amounts of correction, using one coil.

In contrast, in the present invention, the strength of the left and right magnets can be made different in advance, and the mounting positions relative to the deflection yoke can be selected individually or at the same time. It has many degrees of freedom and can provide extremely good correction performance.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a first implementation according to the present invention;
Fig. 2 is a characteristic diagram showing the magnetic field strength distribution of Fig. 1, Fig. 5 is a characteristic diagram showing the second embodiment of the present invention, and Fig. 4 is a characteristic diagram showing the magnetic field strength distribution of Fig. 5. 5A and 5B are explanatory diagrams showing the electrical connection method in the second embodiment. 1... Braun tube 2... Deflection yoke 5.4... Foundation stone 5.6... Winding 15... Horizontal deflection coil 1. ku fan 2 offense 3 prisoner ((L)tshi) ↑ 1- mouth (b)

Claims (1)

[Claims] 1) In a horizontal deflection circuit of a television receiver, magnets are arranged near the left end and near the right end of the opening of a deflection yoke constituting the circuit, and the polarity of both magnets is the same in the vertical direction. A horizontal deflection circuit that corrects the linearity of a horizontal scanning beam by aligning the horizontal scanning beam with the horizontal scanning beam. 2) In the horizontal deflection circuit according to claim 1, each of the magnets is provided with a winding, and among these magnet windings, the magnet winding on the horizontal deflection start end side has a deflection in the first half of the horizontal deflection. A current corresponding to the current is passed in a direction that generates a magnetic flux of the same polarity as the magnetic flux caused by the magnet,
A horizontal deflection circuit characterized in that a current corresponding to a deflection current in the second half of the horizontal deflection is passed through a magnet winding on the end side of the horizontal deflection in a direction in which a magnetic flux having the same polarity as the magnetic flux caused by the magnet is generated.